Monotouch - NSInvalidArgumentException

I've got this error:

2011-03-28 15:38:07.154 FolderNavigation[264:207] -[Subfolder _setViewDelegate:]: unrecognized selector sent to instance 0x6eaafd0

Unhandled Exception: MonoTouch.Foundation.MonoTouchException: Objective-C exception thrown.  Name: NSInvalidArgumentException Reason: -[Subfolder _setViewDelegate:]: unrecognized selector sent to instance 0x6eaafd0
  at (wrapper managed-to-native) MonoTouch.UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
  at MonoTouch.UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Users/plasma/Source/iphone/monotouch/UIKit/UIApplication.cs:26 
  at MonoTouch.UIKit.UIApplication.Main (System.String[] args) [0x00000] in /Users/plasma/Source/iphone/monotouch/UIKit/UIApplication.cs:31 
  at FolderNavigation.Application.Main (System.String[] args) [0x00000] in /Users/claudio/Projects/FolderNavigation/FolderNavigation/Main.cs:16 
Error connecting stdout and stderr (127.0.0.1:10001)

and following de code using Debug(using Step Into)

Starting on Main.cs:

static void Main (string[] args)
{
开发者_运维百科    UIApplication.Main (args);
}

Subfolder.xib.cs(next Step Into)

[Export("initWithCoder:")]
public Subfolder (NSCoder coder) : base(coder)
{
    Initialize ();
}

void Initialize ()
{
}

and in the next step, I have got this error.

Does anybody have an idea?

Thanks in advance!

Is this a View or ViewController? My auto-generated files have a public Subfolder() : base("Subfolder", null) constructor, which I don't see here.

Also, which version of XCode & MT are you running?